Development of deflector mode for spin-resolved time-of-flight photoemission spectroscopy

Spin- and angle-resolved photoemission spectroscopy ("spin-ARPES") is a powerful technique for probing the spin degree-of-freedom in materials with nontrivial topology, magnetism, and strong correlations. Spin-ARPES faces severe experimental challenges compared to conventional ARPES attributed to the dramatically lower efficiency of its detection mechanism, making it crucial for instrumentation developments that improve the overall performance of the technique. In this paper, we demonstrate the functionality of our spin-ARPES setup based on time-of-flight spectroscopy and introduce our recent development of an electrostatic deflector mode to map out spin-resolved band structures without sample rotation. We demonstrate the functionality by presenting the spin-resolved spectra of the topological insulator Bi2Te3 and describe in detail the spectrum calibrations based on numerical simulations. By implementing the deflector mode, we minimize the need for sample rotation during measurements, hence improving the overall efficiency of experiments on small or inhomogeneous samples.

Central odontogenic fibroma with amyloid: a diagnostically challenging case

Odontogenic fibroma is a rare benign mesenchymal odontogenic tumor, with its histological diversity possibly posing diagnostic challenges. A case of the amyloid variant of central odontogenic fibroma, with epithelial cells in perineural and intraneural locations, is reported herein. The 46-year-old female patient had experienced discomfort related to her anterior right hard palate for approximately 25 years. Clinical examination revealed a depression in the anterior hard palate, and radiographic examination showed a well-defined radiolucent lesion with root resorption of the adjacent teeth. Histologically, the well-circumscribed tumor was composed of hypocellular collagenous connective tissue with small islands of odontogenic epithelium. In addition, the juxta-epithelial deposition of amyloid globules without calcification and epithelial cells in perineural and intraneural locations were observed, which posed a diagnostic challenge in differentiating the lesion from the non-calcifying variant of calcifying epithelial odontogenic tumor and sclerosing odontogenic carcinoma. However, on the basis of the clinical and radiographic findings, which were suggestive of a benign and slowly progressive process given the corticated, unilocular radiolucency, the considerable root resorption, and the long history of this finding in an otherwise healthy patient, the final diagnosis was amyloid variant of central odontogenic fibroma. Increased recognition of this variant of odontogenic fibroma and its differentiation from other more aggressive lesions could help the clinician to avoid overdiagnosis and overtreatment.

Observation of large spin conversion anisotropy in bismuth

While the effective g-factor can be anisotropic due to the spin-orbit interaction (SOI), its existence in solids cannot be simply asserted from a band structure, which hinders progress on studies from such viewpoints. The effective g-factor in bismuth (Bi) is largely anisotropic; especially for holes at T-point, the effective g-factor perpendicular to the trigonal axis is negligibly small (<0.112), whereas the effective g-factor along the trigonal axis is very large (62.7). We clarified in this work that the large anisotropy of effective g-factor gives rise to the large spin conversion anisotropy in Bi from experimental and theoretical approaches. Spin-torque ferromagnetic resonance was applied to estimate the spin conversion efficiency in rhombohedral (110) Bi to be 17 to 27%, which is unlike the negligibly small efficiency in Bi(111). Harmonic Hall measurements support the large spin conversion efficiency in Bi(110). A large spin conversion anisotropy as the clear manifestation of the anisotropy of the effective g-factor is observed. Beyond the emblematic case of Bi, our study unveiled the significance of the effective g-factor anisotropy in condensed-matter physics and can pave a pathway toward establishing novel spin physics under g-factor control.

Octupole-driven magnetoresistance in an antiferromagnetic tunnel junction

The tunnelling electric current passing through a magnetic tunnel junction (MTJ) is strongly dependent on the relative orientation of magnetizations in ferromagnetic electrodes sandwiching an insulating barrier, rendering efficient readout of spintronics devices^1-5. Thus, tunnelling magnetoresistance (TMR) is considered to be proportional to spin polarization at the interface¹ and, to date, has been studied primarily in ferromagnets. Here we report observation of TMR in an all-antiferromagnetic tunnel junction consisting of Mn₃Sn/MgO/Mn₃Sn (ref. ⁶). We measured a TMR ratio of around 2% at room temperature, which arises between the parallel and antiparallel configurations of the cluster magnetic octupoles in the chiral antiferromagnetic state. Moreover, we carried out measurements using a Fe/MgO/Mn₃Sn MTJ and show that the sign and direction of anisotropic longitudinal spin-polarized current in the antiferromagnet⁷ can be controlled by octupole direction. Strikingly, the TMR ratio (about 2%) of the all-antiferromagnetic MTJ is much larger than that estimated using the observed spin polarization. Theoretically, we found that the chiral antiferromagnetic MTJ may produce a substantially large TMR ratio as a result of the time-reversal, symmetry-breaking polarization characteristic of cluster magnetic octupoles. Our work lays the foundation for the development of ultrafast and efficient spintronic devices using antiferromagnets^8-10.

QSAR model to predict Kp,uu,brain with a small dataset, incorporating predicted values of related parameter

The unbound brain-to-plasma concentration ratio (K_p,uu,brain) is a parameter that indicates the extent of central nervous system penetration. Pharmaceutical companies build prediction models because many experiments are required to obtain K_p,uu,brain. However, the lack of data hinders the design of an accurate prediction model. To construct a quantitative structure-activity relationship (QSAR) model with a small dataset of K_p,uu,brain, we investigated whether the prediction accuracy could be improved by incorporating software-predicted brain penetration-related parameters (BPrPs) as explanatory variables for pharmacokinetic parameter prediction. We collected 88 compounds with experimental K_p,uu,brain from various official publications. Random forest was used as the machine learning model. First, we developed prediction models using only structural descriptors. Second, we verified the predictive accuracy of each model with the predicted values of BPrPs incorporated in various combinations. Third, the K_p,uu,brain of the in-house compounds was predicted and compared with the experimental values. The prediction accuracy was improved using five-fold cross-validation (RMSE = 0.455, r² = 0.726) by incorporating BPrPs. Additionally, this model was verified using an external in-house dataset. The result suggested that using BPrPs as explanatory variables improve the prediction accuracy of the K_p,uu,brain QSAR model when the available number of datasets is small.

Chirality-Induced Magnetoresistance Due to Thermally Driven Spin Polarization

Chirality-induced current-perpendicular-to-plane magnetoresistance (CPP-MR) originates from current-induced spin polarization in molecules. The current-induced spin polarization is widely recognized as a fundamental principle of chiral-induced spin selectivity (CISS). In this study, we investigate chirality-induced current-in-plane magnetoresistance (CIP-MR) in a chiral molecule/ferromagnetic metal bilayer at room temperature. In contrast to CPP-MR, CIP-MR observed in the present study requires no bias charge current through the molecule. The temperature dependence of CIP-MR suggests that thermally driven spontaneous spin polarization in chiral molecules is the key to the observed MR. The novel MR is consistent with recent CISS-related studies, that is, chiral molecules in contact with a metallic surface possess a finite spin polarization.

A case of nivolumab-induced acute-onset type 1 diabetes mellitus in melanoma

Nivolumab, an anti-PD-1 antibody, is now considered an important therapeutic agent in several advanced malignancies. However, immune-related adverse events such as endocrinopathies have been reported with its use. Thyroid disorder and isolated adrenocorticotropic hormone deficiency have frequently been reported as nivolumab-induced immune-related adverse events. Another endocrinopathy is nivolumab-induced type 1 diabetes mellitus (t1dm), described as diabetes mellitus with rapid onset and complete insulin insufficiency, at times leading to fulminant t1dm. We report the case of a 68-year-old woman who developed pancreatic islet-related autoantibody-negative t1dm, possibly induced by nivolumab, under continuous glucocorticoid administration. She was treated with nivolumab for advanced malignant melanoma, concomitant with 10 mg prednisolone daily for thrombophlebitis tapered to 5 mg after 13 courses of nivolumab therapy. At approximately the 27th course of nivolumab therapy, she showed elevated plasma glucose levels despite preserved insulin secretion. A month later, she developed diabetic ketoacidosis. Her insulin secretion decreased and finally was exhausted. She was diagnosed with acute-onset rather than fulminant t1dm because of a rapidly progressive course to diabetic ketoacidosis during just more than 1 week. She is currently receiving insulin replacement. There has been no recurrence of the melanoma. Thus, nivolumab might induce autoimmune diabetes mellitus, with patients having t1dm-sensitive human leucocyte antigen being more susceptible even when receiving glucocorticoids. Physicians should be aware that nivolumab could potentially induce t1dm as a critical immune-related adverse event.

Imaging Differences between Neuromyelitis Optica Spectrum Disorders and Multiple Sclerosis: A Multi-Institutional Study in Japan

BACKGROUND AND PURPOSE

Both clinical and imaging criteria must be met to diagnose neuromyelitis optica spectrum disorders and multiple sclerosis. However, neuromyelitis optica spectrum disorders are often misdiagnosed as MS because of an overlap in MR imaging features. The purpose of this study was to confirm imaging differences between neuromyelitis optica spectrum disorders and MS with visually detailed quantitative analyses of large-sample data.

MATERIALS AND METHODS

We retrospectively examined 89 consecutive patients with neuromyelitis optica spectrum disorders (median age, 51 years; range, 16-85 years; females, 77; aquaporin 4 immunoglobulin G-positive, 93%) and 89 with MS (median age, 36 years; range, 18-67 years; females, 68; relapsing-remitting MS, 89%; primary-progressive MS, 7%; secondary-progressive MS, 2%) from 9 institutions across Japan (April 2008 to December 2012). Two neuroradiologists visually evaluated the number, location, and size of all lesions using the Mann-Whitney U test or the Fisher exact test.

RESULTS

We enrolled 79 patients with neuromyelitis optica spectrum disorders and 87 with MS for brain analysis, 57 with neuromyelitis optica spectrum disorders and 55 with MS for spinal cord analysis, and 42 with neuromyelitis optica spectrum disorders and 14 with MS for optic nerve analysis. We identified 911 brain lesions in neuromyelitis optica spectrum disorders, 1659 brain lesions in MS, 86 spinal cord lesions in neuromyelitis optica spectrum disorders, and 102 spinal cord lesions in MS. The frequencies of periventricular white matter and deep white matter lesions were 17% and 68% in neuromyelitis optica spectrum disorders versus 41% and 42% in MS, respectively (location of brain lesions, P < .001). We found a significant difference in the distribution of spinal cord lesions between these 2 diseases (P = .024): More thoracic lesions than cervical lesions were present in neuromyelitis optica spectrum disorders (cervical versus thoracic, 29% versus 71%), whereas they were equally distributed in MS (46% versus 54%). Furthermore, thoracic lesions were significantly longer than cervical lesions in neuromyelitis optica spectrum disorders (P = .001), but not in MS (P = .80).

CONCLUSIONS

Visually detailed quantitative analyses confirmed imaging differences, especially in brain and spinal cord lesions, between neuromyelitis optica spectrum disorders and MS. These observations may have clinical implications.

Electronic Structure of Ce-Doped and -Undoped Nd_{2}CuO_{4} Superconducting Thin Films Studied by Hard X-Ray Photoemission and Soft X-Ray Absorption Spectroscopy

In order to realize superconductivity in cuprates with the T^{'}-type structure, not only chemical substitution (Ce doping) but also postgrowth reduction annealing is necessary. In the case of thin films, however, well-designed reduction annealing alone without Ce doping can induce superconductivity in the T^{'}-type cuprates. In order to unveil the origin of superconductivity in the Ce-undoped T^{'}-type cuprates, we have performed bulk-sensitive hard x-ray photoemission and soft x-ray absorption spectroscopy on superconducting and nonsuperconducting Nd_{2-x}Ce_{x}CuO_{4} (x=0, 0.15, and 0.19) thin films. By postgrowth annealing, core-level spectra exhibited dramatic changes, which we attributed to the enhancement of core-hole screening in the CuO_{2} plane and the shift of chemical potential along with changes in the band filling. The result suggests that the superconducting Nd_{2}CuO_{4} film is doped with electrons despite the absence of the Ce substitution.

Effects of biopolyimide molecular design on their silica hybrids thermo-mechanical, optical and electrical properties

Polymers, derived from bio-derived resources, have gained considerable momentum because of a lower dependence over conventional fossil-based resources without compromising the materials' thermo-mechanical properties. Unique characteristics of organic and inorganic materials can be incorporated by a combination of both to obtain hybrid materials. We have recently developed a series of transparent biopolyimides (BPI) from a biologically derived exotic amino acid, 4-aminocinnamic acid (4ACA) to yield 4-amino truxillic ester (4ATA ester) derivatives. In the present research, the polyimide-precursor was subjected to sol–gel polycondensation reactions with silicon-alkoxide followed by annealing under vacuo to yield a biopolyimide-silica hybrid. The biopolyimide structures (4ATA acid/ester) and their silica hybrids thermo-mechanical, electrical and optical performance were evaluated. It was found that the biopolyimide with 4ATA(ester) yields thermo-mechanically robust films with very high electrical stability as well as optical transparency, plausibly due to the uniform dispersion of the silica particles in the biopolyimide matrix.

Biopolyamide structure and their silica hybrids performances were studied. Biopolyamide with inability to interact with silanol during sol–gel condensation for silica formation showed superior thermo-mechanical, optical and electrical properties.

Adhesion patterning by a novel air-lock technique enables localization and in-situ real-time imaging of reprogramming events in one-to-one electrofused hybrids

Although fusion of somatic cells with embryonic stem (ES) cells has been shown to induce reprogramming, single-cell level details of the transitory phenotypic changes that occur during fusion-based reprogramming are still lacking. Our group previously reported on the technique of one-to-one electrofusion via micro-slits in a microfluidic platform. In this study, we focused on developing a novel air-lock patterning technique for creating localized adhesion zones around the micro-slits for cell localization and real-time imaging of post fusion events with a single-cell resolution. Mouse embryonic fibroblasts (MEF) were fused individually with mouse ES cells using a polydimethylsiloxane (PDMS) fusion chip consisting of two feeder channels with a separating wall containing an array of micro-slits (slit width ∼3 μm) at a regular spacing. ES cells and MEFs were introduced separately into the channels, juxtaposed on the micro-slits by dielectrophoresis and fused one-to-one by a pulse voltage. To localize fused cells for on-chip culture and time-lapse microscopy, we implemented a two-step approach of air-lock bovine serum albumin patterning and Matrigel coating to create localized adhesion areas around the micro-slits. As a result of time-lapse imaging, we could determine that cell division occurs within 24 h after fusion, much earlier than the 2-3 days reported by earlier studies. Remarkably, Oct4-GFP (Green Fluorescent Protein) was confirmed after 25 h of fusion and thereafter stably expressed by daughter cells of fused cells. Thus, integrated into our high-yield electrofusion platform, the technique of air-lock assisted adhesion patterning enables a single-cell level tracking of fused cells to highlight cell-level dynamics during fusion-based reprogramming.

Functional outcome and quality of life after traumatic total brachial plexus injury treated by nerve transfer or single/double free muscle transfers

Aims

Between 2002 and 2011, 81 patients with a traumatic total brachial plexus injury underwent reconstruction by double free muscle transfer (DFMT, 47 cases), single muscle transfer (SMT, 16 cases) or nerve transfers (NT, 18 cases).

Methods

They were evaluated for functional outcome and quality of life (QoL) using the Disability of Arm, Shoulder and Hand questionnaire, both pre- and post-operatively. The three groups were compared and followed-up for at least 24 months.

Results

The mean shoulder abduction and flexion were comparable in all groups, but external rotation was significantly better in the DFMT group as were range and quantitative power of elbow flexion. Patients who had undergone DFMT had reasonable total active finger movement and hook grip strength. All groups showed improvement in function at a level greater than a minimum clinically important difference. The DFMT group showed the greatest improvement.

Discussion

Patients in the DFMT group had a better functional outcome and QoL recovery than those in the NT and SMT groups. Take home message: Double free muscle transfer procedure is capable of restoring maximum function in patients of total brachial plexus palsy. Cite this article: Bone Joint J 2016;97-B:209–17.

Outcome of arthroscopic reduction association of the scapholunate joint

This study evaluates the arthroscopic reduction association scapholunate technique and outcomes. A total of 18 patients with chronic scapholunate instability with mean follow-up of 36 months were reviewed. Postoperatively, the mean visual analogue score was 2.5 and the mean DASH score was 8. The grip strength was 27 kg on the operative side compared with 32 kg on the uninjured side. The mean wrist flexion was 46° and extension was 56°. Seven patients had complications. Six patients had scapholunate joint widening, one had windshield-wipering of the screws with loss of reduction, and two demonstrated progression of scapholunate advanced collapse deformity. Four patients underwent revision surgeries: two revision arthroscopic reduction association scapholunates and two proximal row carpectomies. A preoperative scapholunate gap of greater than 5 mm and the presence of scapholunate advanced collapse Grade I were both predictive of a complication or revision surgery. Patients with a scapholunate gap of greater than 5 mm or scapholunate advanced collapse had statistically higher complications rates.Level of Evidence IV.

Contralateral lower trapezius transfer for restoration of shoulder external rotation in traumatic brachial plexus palsy: a preliminary report and literature review

The importance of external rotation of the shoulder is well accepted. Patients with inadequate recovery of shoulder function after nerve transfers for a brachial plexus injury have difficulty in using their reconstructed limb. The options for secondary procedures to improve shoulder function are often limited, especially if the spinal accessory nerve has been used earlier for nerve transfer or as a donor nerve for a free functioning muscle transfer. We have used the contralateral lower trapezius transfer to the infraspinatus in three cases, to restore shoulder external rotation. All patients had significant improvement in shoulder external rotation (mean 97°; range 80°-110°) and improved disability of the arm, shoulder and hand scores. The rotation occurred mainly at the glenohumeral joint, and was independent of the donor side. All patients were greatly satisfied with the outcome. Contralateral lower trapezius transfer appears to help in overall improvement of shoulder function by stabilizing the scapula. The results have remained stable after mean follow-up of 58 months (range 12-86). No donor site deficit was seen in any patient.

Prediction of low-frequency structure-borne sound in concrete structures using the finite-difference time-domain method

Due to limitations of computers, prediction of structure-borne sound remains difficult for large-scale problems. Herein a prediction method for low-frequency structure-borne sound transmissions on concrete structures using the finite-difference time-domain scheme is proposed. The target structure is modeled as a composition of multiple plate elements to reduce the dimensions of the simulated vibration field from three-dimensional discretization by solid elements to two-dimensional discretization. This scheme reduces both the calculation time and the amount of required memory. To validate the proposed method, the vibration characteristics using the numerical results of the proposed scheme are compared to those measured for a two-level concrete structure. Comparison of the measured and simulated results suggests that the proposed method can be used to simulate real-scale structures.

Effect of occlusal rehabilitation on spatial memory and hippocampal neurons after long-term loss of molars in rats

Experimental loss of occlusal support caused by the extraction or grinding of molar teeth has been reported to foment the impairment of learning and memory in laboratory animals. The purpose of this study was to examine the effect of occlusal reconstruction after long-term loss of molars on spatial memory by using 8-arm radial maze and by assessing histopathological changes of neuron density in the hippocampus. Experimental dentures were inserted into the oral cavities of molarless rats to recover the occlusal support. Age-matched groups of control, molarless and denture-wearing rats were trained to perform the maze tasks. The difference of the error incidence in the maze task was evaluated between three groups. The difference of neuron density between three groups was also evaluated at the end of the maze task. Serum corticosterone levels were also measured to estimate the chronic stress, which could be caused by extraction, insertion of the experimental denture or any experimental procedure. The error incidence in the denture-wearing group was significantly higher than that of the control group, but significantly lower than that of the molarless group. Significant differences of neuron density were observed between three groups in each of the hippocampal CA1, CA3 and DG subfields. No significant difference of the serum corticosterone levels between three groups could be observed. From the results of this study, it was suggested that the recovery of occlusal support would bring amelioration of cognitive impairment concomitant with long period loss of molars in rats.

Modified osteotomy (Kanaya's procedure) for congenital proximal radioulnar synostosis with posterior dislocation of radial head

Outcomes of Kanaya's procedure for congenital proximal radioulnar synostosis varied depending on the type of radial head dislocation. In our series of 14 patients with 17 forearms who underwent Kanaya's original procedure, the postoperative total rotation arc of the forearm was unsatisfactory in cases with posterior radial head dislocation. We examined the outcomes with respect to the type of radial head dislocation and radial shaft curvature. Radial shafts with a posterior radial head dislocation had only one curve and the radii of the curve were statistically smaller than those in anterior dislocated or enlocated heads, which had two curves. As a result, we modified the osteotomy site for proximal radioulnar synostosis with posterior radial head dislocation and achieved improved forearm rotation and physiological rotation of the radial head in our latest two cases.

Clinical outcomes and evaluation of the quality of life of living donors for pediatric liver transplantation: a single-center analysis of 100 donors

There are few reports about the quality of life (QOL) and morbidities of pediatric living donor liver transplantation (LDLT) donors. We evaluated the potential morbidities and identified the predictive factors regarding the QOL of living donors after pediatric LDLT. This cross-sectional study was a single-center analysis of 100 donors for pediatric LDLT. The severity of morbidities was assessed with the Clavien classification, the QOL was investigated with the short form-36 (SF-36), and the decision-making process regarding donation was analyzed with questionnaires. The median follow-up period was 3.8 years (range, 2.2-6.0 years). A total of 13% of the donors developed postoperative complications of Clavien grades I (7%), II (3%), and IIIA (3%). There was no grade IV morbidity or mortality. Eighty-one donors responded to the questionnaire and SF-36. The analysis of the questionnaires revealed that the donors had difficulty in the decision-making process, and suggested that it may be necessary to administer multistep informed consent. We identified unique predictive risk factors for lower SF-36 scores in the donors, which were the time to donation (more than 4 weeks) and the predonation self-oriented perception. The donors who have risk factors require enhanced pre- and post-donation psychological care.